1. Field of the Invention
The invention relates to a hinge unit that is capable of positively preventing rotation from exceeding a fully open position and an electronic apparatus equipped with the hinge unit.
2. Description of the Related Art
There has been known an electronic apparatus, such as a digital camera, which is configured to be capable of subjecting a display unit thereof to rotating operation with respect to an apparatus body via a hinge unit in an opening direction through approximately 180 degrees, thereby causing the display screen of the display unit to be positioned at a location above the apparatus body in a manner facing toward an object, such that a user can perform self-photographing in which the user photographs himself/herself.
In general, in an electronic apparatus of the above-mentioned type, when a display unit thereof is brought into a fully open state by being rotationally operated with respect to an apparatus body via a hinge unit through approximately 180 degrees, the exterior of the display unit is brought into abutment with that of the apparatus body, whereby further rotation of the display unit is restricted.
However, in the above-described rotation restriction structure, when the hinge unit has a rotational shaft having its axial center position located close to the top surface of the apparatus body in the vertical direction, it is impossible to positively restrict the rotation of the display unit even though the exterior of the apparatus body and the exterior of the display unit have respective portions for abutment. For this reason, there is a possibility that the display unit rotates through more than 180 degrees.
To avoid this, there has been proposed a technique for restricting a rotational angle between a first gear part fitted on the outer periphery of a first rotational shaft fixed to the apparatus body and a second gear part fitted on the outer periphery of a second rotational shaft to which the display unit is fixed (see Japanese Patent Laid-Open Publication No. 2005-23955). According to this proposal, each of the first gear part and the second gear part has protrusions formed such that each of the protrusions is brought into engagement with an associated recess formed in a separate member at each rotational angle. Note that the separate member is urged by an urging member, such as a coil spring, in a direction for engagement of the recess with the protrusion.
Incidentally, an electronic apparatus having a display unit supported on its apparatus body via a hinge unit in a manner rotatable in an opening/closing direction inevitably has a size larger than that of an electronic apparatus having a display unit integrally incorporated in its apparatus body. For this reason, in order to meet the recent demand for reduction of the size of an electronic apparatus, such as a digital camera, it is desirable to reduce the size of the display unit including the hinge unit.
However, the technique proposed in Japanese Patent Laid-Open Publication No. 2005-23955 requires the hinge unit including the first rotational shaft, the second rotational shaft, the first gear part, the second gear part, the separate member, and the urging member, and hence the number of components is large, resulting in an increase in the size of the hinge unit. Therefore, the size of the display unit including the hinge unit is increased, which causes an increase in the size of the whole apparatus.